(d)Given differential equation is P2+q2=x+y where p=∂x∂z,q=∂y∂zLet us take option (d) as solutionsz=32(a+x)23+32(y−a)23+bp=∂x∂z=32⋅23(a+x)23−1+0+0=a+xq=∂y∂z=32⋅23⋅(y−a)23−1=y−aNow p2+q2=(a+x)+(y−a)=x+y which is (1)Hence, the correct option is (d).